ESR1 and breast cancer: This locus contains 24 protein-coding genes (Supplementary Figure S7C), among which at least 10 (e.g. NCOA3, SNAI1/Snail1, CEBPB and PTPN1) are involved in mammary gland development, ERα-related regulation, or breast cancer (Supplementary Table S1), suggesting an importance of this locus for mammary gland morphogenesis.